Growth and properties analysis of AlxGa2-xO3 thin film by radio frequency magnetron sputtering using Al/Ga2O3 target

In this work, (AlxGa1-x)2O3 thin films were grown on Al2O3 (0001) substrate by radio frequency magnetron sputtering using Al/Ga2O3 target. The analysis of crystalline structure, morphology, transmittance and bandgap after various annealing temperatures were investigated in detail. The films were oriented along (2—01) plane, and the crystalline quality improved with increasing annealing temperature. The stoichiometries of films can be regard as (Al0.33Ga0.67)2O3 according to X-ray photoelectron spectroscopy and the additional compressive stress in the sample which annealed at 900 °C was certified. The bandgap of annealed films was totally decreased due to increasing magnitude of compressive stress and grain size. Therefore, these results may suggest the way to tune the band gap of β-(AlxGa1-x)2O3 films by varying the residual stress through annealing and indicate the optimum annealing temperature for (Al0.33Ga0.67)2O3 thin films is about 800 °C. •The (AlxGa1-x)2O3 films were deposited using Al/Ga2O3 target.•All the samples were monoclinic structure with the (−201) preferred orientation.•Post-annealing can improve the crystalline of (AlxGa1-x)2O3 thin films.•The remigration of Al atoms took place after annealing at 900 °C.